Mining system

ABSTRACT

A method of mining ore in a mine pit ( 3 ) and a mine are disclosed. The method comprises drilling and blasting ore in a bench ( 19 ) of ore within the mine pit and collecting ore blasted from the bench from a floor ( 5 ) of the mine pit using at least one mobile excavation machine ( 11 ). The method also comprises delivering ore that has been collected by the mobile excavation machine to at least one mobile-in-pit crusher ( 41 ), and transporting crushed ore to outside the pit on at least one ladder conveyor ( 23 ) that extends up the wall of the pit.

The present invention relates to mining ore that contains valuablemetals.

The present invention relates particularly, although by no meansexclusively to mining iron ore.

Conventional open pit mining of iron ore comprises progressivelydrilling and blasting sections of an ore body so that the ore can bepicked up by shovels or other suitable excavators and transported from apit on haulage trucks. It is known to mine iron ore in large blocksusing a series of benches so that various mining activities can becarried out concurrently in a pit. A bench, which may be for example40-200 m long by 20-100 m deep by 10-15 m high and containing manythousands of tonnes of ore and/or other material, is first drilled toform a pattern of “blast” holes. The material removed during the courseof drilling the blast holes is analysed, for example by chemicalanalysis, to determine whether, on average, the ore is (a) high grade,(b) low grade or (c) waste material. The cut-off between high and lowgrades is dependent on a range of factors and may vary from mine to mineand in different sections of mines. The bench of ore is blasted usingexplosives, typically ANFO (ammonium nitrate/fuel oil) based, that aredispensed in specially designed bulk dispensing trucks which canregulate the explosive density prior to loading down the blast holes.The blasted material is picked up by earth moving vehicles in the formof excavators such as electric rope shovels, diesel hydraulicexcavators, or front end loaders and placed into haulage vehicles suchas trucks and transported from the mine pit. The ore is processedoutside the mine pit depending on the grade determination. For example,waste ore is used as mine fill, low grade ore is stockpiled or used toblend with high grade ore, and high grade ore is processed further asrequired to form a marketable product.

The present invention is an alternative mining method to theabove-described method.

The mining method of the present invention may be used as the onlymethod of mining in a mine pit or as one of several mining methods in amine pit.

According to the present invention there is provided a method of miningore in a mine pit that comprises the steps of:

(a) drilling and blasting ore in a bench of ore within the mine pit;

(b) collecting ore blasted from the bench from a floor of the mine pitusing at least one mobile excavation machine;

(c) delivering ore that has been collected by the mobile excavationmachine to at least one mobile in-pit crusher and crushing ore to anoverall reduced size ore; and

(d) transporting crushed ore to outside the pit on at least one ladderconveyor that extends up the wall of the pit.

The mobile excavation machine may be in the form of an electric ropeshovel, a diesel hydraulic excavator, or a front end loader, or anyother suitable machine for collecting mined ore from the pit floor.

Step (c) of the method may comprise delivering ore that has beencollected by the mobile excavation machine to at least one mobileflexible conveyor within the mine pit and transporting ore from theexcavation machine on the conveyor and delivering ore to the in-pitcrusher and crushing ore to the overall reduced size ore.

The term “mobile flexible conveyor” is understood herein to mean aconveyor that is both mobile and flexible and can move across the floorof the mine pit in a linear and a non-linear manner and can continue tooperate while moving across the pit floor.

The term “mobile flexible conveyor” does not include conveyors thatpersons in the mining industry refer to as “shiftable” or “movable”conveyors, as described above. A “shiftable” or “movable” conveyor is aconveyor that can be repositioned in a mine after a period of mining hasbeen completed. In other words, the conveyor is not mobile in the sensethat it can move continuously, for example, to keep pace with a mobileexcavation machine or other mobile machine while continuing to operateto transported ore along the conveyor.

Typically, the mobile flexible conveyor has to meet any one or more ofthree basic requirements, namely (a) be sufficiently mobile to keep pacewith an associated mobile excavation machine or other mobile machinewhile operating and transporting ore on the conveyor, (b) allow lateral,flexible movement whilst operating and transporting ore on the conveyorand, by way of example be capable of moving up or down steps of up to400 mm in a pit floor, and (c) allow lengthwise extension andcontraction while operating and transporting ore on the conveyor.

The mobile flexible conveyor may be of a type described in Australianpatent 767395 in the name of Michael Pietsch. The disclosure in theAustralian patent is incorporated herein by cross-reference.

The method may comprise delivering ore that has been collected by themobile excavation machine to at least one mobile holding and feedingdevice within the mine pit and delivering the ore via the mobile holdingand feeding device to the mobile flexible conveyor.

The method may comprise delivering ore via multiple flexible mobileconveyors to the in-pit crusher.

The in-pit crusher may be located proximate blasted ore to minimise thetravel distance to the crusher.

In this connection, the in-pit crusher may be a mobile crusher and themethod may comprise moving the crusher about the mine pit from time totime in response to increasing pit depth and/or change of location ofmining activities.

The method may comprise transporting crushed ore from the in-pit crusherin at least one haulage truck within the mine pit to the ladderconveyor.

The method may comprise transporting crushed ore from the in-pit crusheron at least one mobile trunk conveyor that extends along a section ofthe pit floor to the ladder conveyor.

The term “mobile trunk conveyor” is understood herein to mean conveyorsthat persons in the mining industry refer to as “shiftable” or “movable”conveyors. A “shiftable” or “movable” conveyor is a conveyor that can berepositioned in a mine after a period of mining has been completed. Inother words, the conveyor is not mobile in the sense that it can movecontinuously, for example, to keep pace with a mobile machine whilecontinuing to operate to transport ore along the conveyor. The conveyoris mobile in the sense that it can be shifted or moved periodically to anew location.

The mobile trunk conveyor may be located on the pit floor in a lowerregion of the pit.

The mobile trunk conveyor may follow a linear path or a non-linear path.

The method may comprise periodically adjusting the mobile trunk conveyorin response to a lowering of the pit floor from time to time.

The in-pit crusher may be located proximate the ladder conveyor.

In that event, the method may comprise delivering ore that has beencollected by the mobile excavation machine to at least one mobile trunkconveyor that extends from a location proximate the blasted ore andalong a section of the pit floor to the in-pit crusher.

In addition, in that event, the method may comprise (a) delivering orethat has been collected by the mobile excavation machine to at least onemobile flexible conveyor located proximate the blasted ore, (b)transporting the ore along the mobile flexible conveyor to the trunkconveyor, and (c) transporting the ore along the trunk conveyor to thein-pit crusher.

The term “ladder conveyor” as used herein is understood to mean aconveyor that is able to transport ore from a mine pit directly up awall of the mine pit from the pit floor, with the wall being a steepwall at an angle of at least 20° to the horizontal.

The wall of the mine pit may be at least 30°, in many instances at least65° to the horizontal.

The pit wall may be at least 20 m and typically at least 40 m.

The ladder conveyor may be a single conveyor from the pit floor to a rimof the pit and extend up the pit wall without transfer points along thelength of the conveyor, i.e. without the ore being off-loaded at anupper end of one section of the conveyor and loaded onto a lower end ofa successive section of the conveyor.

The ladder conveyor may extend up the pit wall without a switchback.

The method may comprise extending the ladder conveyor in response to ageneral lowering of the pit floor.

The method may comprise transferring crushed ore that has beentransported up the wall of the pit along the ladder conveyor onto atleast one main conveyor and transporting the ore along the main conveyorto a processing plant and/or a load out station.

Step (d) may comprise transporting crushed ore to outside the pit on atleast two ladder conveyors that extend up the wall of the pit andtransferring crushed ore onto the main conveyor via separate transferpoints for each ladder conveyor.

The main conveyor may be located generally on a rim of the pit or at abase of a local topography surrounding the pit and follows thetoypography thereof.

The main conveyor may receive ore from more than one part of the pit orfrom a series of pits.

According to the present invention there is also provided a mine thatcomprises at least one pit having a pit floor and a pit wall thatdefines at least a part of the pit, at least one mobile excavationmachine for collecting ore that has been blasted from a bench in thepit, at least one mobile-in-pit crusher for crushing the ore to anoverall reduced size ore, and at least one ladder conveyor that extendsup the wall of the pit for transporting crushed ore from the pit.

The mine may comprise at least one flexible mobile conveyor in the pitfor transporting ore from the excavation machine and delivering ore tothe in-pit crusher.

Typically, the mobile flexible conveyor has to meet any one or more ofthree basic requirements, namely (a) be sufficiently mobile to keep pacewith an associated mobile excavation machine or other mobile machinewhile operating and transporting ore on the conveyor, (b) allow lateral,flexible movement whilst operating and transporting ore on the conveyorand, by way of example be capable of moving up or down steps of up to400 mm in a pit floor, and (c) allow lengthwise extension andcontraction while operating and transporting ore on the conveyor.

The mine may comprise at least one mobile trunk conveyor that extendsalong a section of the pit floor for transporting ore at least a part ofthe distance from the mobile excavating machine to the ladder conveyor.

The in-pit crusher may be located proximate the mining activity in themine to minimise travel distance to the crusher.

The in-pit crusher may be a mobile crusher.

The in-pit crusher may be located proximate the ladder conveyor.

In that event, the mine may comprise at least one mobile trunk conveyorthat extends along a section of the pit floor for transporting ore atleast a part of the distance from the mobile excavating machine to thein-pit crusher.

In addition, in that event, the mine may comprise at least one mobileflexible conveyor within the mine pit for transporting mined ore fromthe mobile excavating machine to the mobile trunk conveyor.

The pit wall may be a steep wall, i.e. at least 20°, more typically atleast 30°, in many instances at least 65° to the horizontal.

The pit wall may be at least 20 m and typically at least 40 m high.

The ladder conveyor may be a single conveyor from the pit floor to therim of the mine pit and extends up the pit wall without transfer pointsalong the length of the conveyor, i.e. without the ore being off-loadedat an upper end of one section of the conveyor and loaded onto a lowerend of a successive section of the conveyor.

The ladder conveyor may extend up the pit wall without a switchback.

The mine may comprise a main conveyor outside the pit for transportingmined and/or collected ore from the pit to a processing plant or aload-out station.

There may be at least two ladder conveyors that extend up the wall ofthe pit for transferring crushed ore onto the main conveyor.

There may be separate transfer points for each ladder conveyor.

The mine may comprise a plurality of pits and at least one main conveyoroutside the pits for transporting mined and/or collected ore from thepits to a processing plant or a load-out station.

The mine may be an iron ore mine.

The present invention is now described by way of example only withreference to the accompanying drawings of which:

FIG. 1 is a schematic diagram of a layout of a mine pit that illustratesa number of embodiments of the method of mining iron ore in accordancewith the present invention and a number of embodiments of the mine inaccordance with the present invention; and

FIG. 2 is a schematic diagram of a layout of a mine pit that illustratesa number of other embodiments of the method of mining iron ore inaccordance with the present invention and a number of other embodimentsof the mine in accordance with the present invention.

The following description of both Figures is in the context of miningiron ore. It is understood that the present invention is not limited tomining iron ore and extends to mining other ores.

It is also understood that the mine layouts shown in both Figures areschematic and are intended to represent mine layouts in a very generalsense.

The same reference numerals are used in both Figures to describe thesame features.

With reference to FIG. 1, a mine pit generally identified by the numeral3 and having a pit floor 5 is defined at least in part by mine walls 7.The mine walls 7 are shown as opposed straight walls for convenienceonly and the present invention is not limited to this arrangement. Thepit floor 5 may be at one level. Alternatively, as shown in the Figure,the pit floor 5 is on multiple levels which form a series of benches,which may be isolated from each other or interconnected by ramps 33.

Each mine wall 7 may comprise a series of steps or be one continuouswall.

The mine pit 5 comprises two benches 19 that are being drilled andblasted in blocks, typically for example 40 m long by 20 m deep by 10 mhigh and containing 8,000 tonnes of ore, by mobile drilling machines 51and produce blasted ore on the lower benches of the pit floor 5. Theblasted ore varies in size from large rocks to fines.

A plurality of mobile excavation machines 11 collect blasted ore fromthe pit floor 5. The mobile excavation machines 11 may be any suitabletype of machine. By way of example, the mobile excavation machines 11may be in the form of electric rope shovels, diesel hydraulicexcavators, or front end loaders.

The mobile excavation machines 11 (and other equipment) shown in FIG. 1may be controlled remotely or by operators on the machines. In eithercase, typically the paths of movement of the mobile excavation machines11 (and other equipment) within the mine pit 3 are in accordance with amining plan.

One group of the mobile excavation machines 11 shown in FIG. 1 transferscollected ore directly onto in-pit crushers 41. The mobile crushers 41reduce the size of the ore to a suitable size for downstream materialshandling and processing. This option is identified by the letters “A” inFIG. 1.

The crushed ore is transported from the in-pit crushers 41 to ladderconveyors 23, i.e. “shiftable” or “movable” conveyors, either by amobile trunk conveyor 27 or by trucks 37.

Another group of mobile excavation machines 11 shown in the Figuretransfers collected ore onto mobile flexible conveyors 13 and theconveyors 13 transport the ore to a mobile feed system 15 located at aforward end of a mobile trunk conveyor 27 and the conveyor 27 transportsthe ore to an in-pit crusher 41 located proximate the ladder conveyors23. This option is identified by the letter “B in the Figure.

Another group of mobile excavation machines 11 shown in the Figuretransfers collected ore directly onto the mobile feed system 15 locatedat the forward end of the mobile trunk conveyor 27 and the conveyor 27transports the ore to the in-pit crusher 41 located proximate the ladderconveyors 23. This option is identified by the letter “C” in FIG. 1.

The mobile crushers 41 may be of any suitable type.

The mobile feed systems 15 may be hoppers or be any other suitable feedsystem.

The mobile flexible conveyors 13 may be of any suitable type. By way ofexample, the mobile flexible conveyors 13 may be as manufactured byInternational Conveying Systems International and described inAustralian patent 767395 in the name of Michael Pietsch.

The mobile trunk conveyors 27 may be of any suitable type. By way ofexample, the mobile trunk conveyors 27 may be the same design as themobile flexible conveyors 13, such as manufactured by InternationalConveying Systems International and described in Australian patent767395, but operated in a more static mode.

The mobile flexible conveyors 13 and the mobile trunk conveyors 27 makeit possible to reduce the reliance on trucks for transporting mined orefrom a mine pit 3. This is a benefit in terms of operating costs,particularly in large, deep mine pits where travel distances and timefrom mining areas to crushers and other processing equipment can besignificant.

The ladder conveyors 23 are arranged to transport ore directly up thewall 7. The ladder conveyors may be in fixed locations against the sidewall 7 or may be mounted for movement along the length of the side wall7. In the latter case, the trunk conveyors 27 are arranged to beshiftable or movable or otherwise be able to be extended to accommodatechanges in location of the ladder conveyors 23. In both cases, theladder conveyors 23 may be extendable in length as the pit depthincreases.

The ladder conveyors 23 may be any suitable conveyor. By way of example,the ladder conveyor 23 may be of the type manufactured by InternationalConveying Systems International and described in Australian patent767395 in the name of Michael Pietsch.

The ladder conveyors 23 transfer the crushed ore via separate transferpoints 61 onto a conveyor assembly 29 that extends along the rim of themine pit 3 and interconnects a series of pits and/or different sectionsof the same pit and transports the ore to a processing station, such asa crusher.

The conveyor assembly 29 may be of a type that facilitates separation ofore into two process streams, with one stream, such as a high grade ore,being transported for processing in a crusher, and the other stream,such as waste ore, being transported to a stockpile for subsequent useas a fill material.

It is relevant to note that the arrangement shown in FIG. 1 represents asection of a pit only and the mining method illustrated with referenceto the Figure is repeated in other sections of the pit 3. It may also bethe case that other mining methods are used in different sections of thepit 3. In any event, the mined ore is transported from the mine vialadder conveyors 23 and is delivered to the conveyor assembly 29.

As is indicated above, FIG. 2 is a schematic diagram of a layout of amine pit that illustrates a number of other embodiments of the method ofmining iron ore in accordance with the present invention and a number ofother embodiments of the mine in accordance with the present invention.

With reference to FIG. 2, a mine pit generally identified by the numeral3 and having a pit floor 5 is defined at least in part by mine walls 7.The mine walls 7 are shown as opposed straight walls for convenienceonly and the present invention is not limited to this arrangement. Thepit floor 5 may be at one level. Alternatively, as shown in the Figure,the pit floor 5 is on multiple levels which form a series of benches,which may be isolated from each other or interconnected by ramps (notshown).

Each mine wall 7 may comprise a series of steps or be one continuouswall.

The mine pit 5 shown in FIG. 2 comprises two benches 19 that are beingdrilled and blasted in blocks, typically for example 40 m long by 20 mdeep by 10 m high and containing 8,000 tonnes of ore, by mobile drillingmachines 51 and produce blasted ore. The blasted ore varies in size fromlarge rocks to fines.

A plurality of mobile excavation machines 11 collect blasted ore fromthe pit floor 5. The mobile excavation machines 11 may be any suitabletype of machine. By way of example, the mobile excavation machines 11may be in the form of electric rope shovels, diesel hydraulicexcavators, or front end loaders.

The mobile excavation machines 11 (and other equipment) may becontrolled remotely or by operators on the machines. In either case,typically the paths of movement of the surface miners 11 (and otherequipment) within the mine pit 3 are in accordance with a mining plan.

One group of the mobile excavation machines 11 shown in FIG. 2 transfersmined ore directly onto mobile flexible conveyors 13.

Another group of mobile excavation machines 11 shown in FIG. 2 transferscollected ore via mobile feed systems 15 located at forward ends of theconveyors 13.

The mobile feed systems 15 may be hoppers or be any other suitable feedsystem.

The mobile flexible conveyors 13 make it possible to operate a minewithout trucks as a main option for transporting mined ore from a minepit 3. This is a benefit in terms of operating costs, particularly inlarge, deep mine pits where travel distances and time from mining areasto crushers and other processing equipment can be significant.

The mobile flexible conveyors 13 may be of any suitable type. By way ofexample, the mobile flexible conveyors 13 may be as manufactured byInternational Conveying Systems International and described inAustralian patent 767395.

The collected ore is transported via the mobile flexible conveyors 13within the mine pit 5 to mobile crushers 41 located on the pit floor 5.The mobile crushers 41 reduce the size of the ore to a suitable size fordownstream materials handling and processing.

The mobile crushers 41 may be of any suitable type.

The crushed ore produced by the mobile crushers 41 is transported either(a) directly to ladder conveyors 23 that are arranged to transportcrushed ore from the mine pit 3 up the mine wall 7 or (b) to internaltrunk conveyors 27 that extend along the pit floor 5 and transport theore to the ladder conveyors 23.

The ladder conveyors 23 may be in fixed locations against the side wall7 or may be mounted for movement along the length of the side wall 7. Inthe latter case, the trunk conveyors 27 are arranged to be movable orotherwise be able to be extended to accommodate changes in location ofthe ladder conveyors 23. In both cases, the ladder conveyors 23 may beextendable in length as the pit depth increases.

The ladder conveyors 23 may be any suitable conveyor. By way of example,the ladder conveyors 23 may be of the type manufactured by InternationalConyeying Systems International and described in Australian patent767395 in the name of Michael Pietsch.

The ladder conveyors 23 transfer the crushed ore via separate transferpoints 61 onto a conveyor assembly 29 that extends along a rim of themine pit 3 and interconnects a series of pits and/or different sectionsof the same pit and transports the ore to a processing station, such asa crusher.

The conveyor assembly 29 may be of a type that facilitates separation ofore into two process streams, with one stream, such as a high grade ore,being transported for processing in a crusher, and the other stream,such as waste ore, being transported to a stockpile for subsequent useas a fill material.

It is relevant to note that the arrangement shown in FIG. 2 represents asection of a pit only and the mining method illustrated with referenceto the Figure is repeated in other sections of the pit 3. It may also bethe case that other mining methods are used in different sections of thepit 3. In any event, the mined ore is transported from the mine vialadder conveyors 23 and is delivered to the conveyor assembly 29.

Many modifications may be made to the method of the present inventionsummarised in the Figure and described above without departing from thespirit and scope of the present invention.

1-28. (canceled)
 29. A method of mining ore in a mine pit that comprisesthe steps of: (a) drilling and blasting ore in a bench of ore within themine pit; (b) collecting ore blasted from the bench from a floor of themine pit using at least one mobile excavation machine; (c) deliveringore that has been collected by the mobile excavation machine to at leastone mobile-in-pit crusher for crushing ore to an overall reduced sizeore; and (d) transporting crushed ore to outside the pit on at least oneladder conveyor that extends up the wall of the pit.
 30. The methoddefined in claim 29, wherein step (c) comprises delivering ore that hasbeen collected by the mobile excavation machine to at least one mobileflexible conveyor within the mine pit and transporting ore away from theexcavation machine on the conveyor and delivering ore to the in-pitcrusher and crushing ore to the overall reduced size ore.
 31. The methoddefined in claim 30, wherein the mobile flexible conveyor meets any oneor more of three basic requirements, namely (a) is sufficiently mobileto keep pace with an associated mobile excavation machine or othermobile machine while operating and transporting ore on the conveyor, (b)allows lateral, flexible movement whilst operating and transporting oreon the conveyor and, by way of example be capable of moving up or downsteps of up to 400 mm in a pit floor, and (c) allows lengthwiseextension and contraction while operating and transporting ore on theconveyor.
 32. The method defined in claim 30 or claim 31, comprisingdelivering ore that has been collected by the mobile excavation machineto at least one mobile holding and feeding device within the mine pitand delivering the ore via the mobile holding and feeding device to themobile flexible conveyor.
 33. The method defined in claim 29, whereinthe in-pit crusher is located proximate blasted ore to minimise thetravel distance to the crusher.
 34. The method defined in claim 33,wherein the in-pit crusher is a mobile crusher and the method comprisesmoving the crusher about the mine pit from time to time in response toincreasing pit depth and/or change of location of mining activities. 35.The method defined in claim 29, comprising transporting crushed ore fromthe in-pit crusher in at least one haulage truck within the mine pit tothe ladder conveyor.
 36. The method defined in claim 29, comprisingtransporting crushed ore from the in-pit crusher on at least one mobiletrunk conveyor that extends along a section of the pit floor to theladder conveyor.
 37. The method defined in claim 29, comprisingdelivering ore that has been collected by the mobile excavation machineto at least one mobile trunk conveyor that extends from a locationproximate the blasted ore and along a section of the pit floor to thein-pit crusher located proximate the ladder conveyor.
 38. The methoddefined in claim 37, comprising (a) delivering ore that has beencollected by the mobile excavation machine to at least one mobileflexible conveyor located proximate the blasted ore, (b) transportingthe ore along the mobile flexible conveyor to at least one trunkconveyor that extends along a section of the pit floor to the in-pitcrusher, and (c) transporting the ore along the trunk conveyor to thein-pit crusher.
 39. The method defined in claim 29, comprisingtransferring crushed ore that has been transported up the wall of thepit along the ladder conveyor onto at least one main conveyor andtransporting the ore along the main conveyor to a processing plantand/or a load out station.
 40. A mine that comprises at least one pithaving a pit floor and a pit wall that defines at least a part of thepit, at least one mobile excavation machine for collecting ore that hasbeen blasted from a bench in the pit, at least one mobile in-pit crusherfor crushing the ore to an overall reduced size ore, at least one ladderconveyor that extends up the wall of the pit for transporting crushedore from the pit.
 41. The mine defined in claim 40, comprising at leastone flexible mobile conveyor in the pit for transporting ore away fromthe excavation machine and delivering ore to the in-pit crusher.
 42. Themine defined in claim 41, wherein the mobile flexible conveyor meets anyone or more of three basic requirements, namely (a) is sufficientlymobile to keep pace with an associated mobile excavation machine orother mobile machine while operating and transporting ore on theconveyor, (b) allows lateral, flexible movement whilst operating andtransporting ore on the conveyor and, by way of example be capable ofmoving up or down steps of up to 400 mm in a pit floor, and (c) allowslengthwise extension and contraction while operating and transportingore on the conveyor.
 43. The mine defined in claim 40, comprising atleast one mobile trunk conveyor that extends along a section of the pitfloor for transporting blasted ore at least a part of the distance fromthe mobile excavating machine to the ladder conveyor.
 44. The minedefined in claim 40, comprising at least one mobile flexible conveyorwithin the mine pit for transporting mined ore at least a part of thedistance from the mobile excavating machine to the in-pit crusher. 45.The mine defined in claim 40, wherein the pit wall is a steep wall, i.e.at least 20°, more typically at least 30°, in many instances at least65° to the horizontal.
 46. The mine defined in claim 40, wherein the pitwall is at least 20 m and typically at least 40 m high.
 47. The minedefined in claim 40, wherein the ladder conveyor is a single conveyorfrom the pit floor to a rim of the mine pit and extends up the pit wallwithout transfer points along the length of the conveyor, i.e. withoutthe ore being off-loaded at an upper end of one section of the conveyorand loaded onto a lower end of a successive section of the conveyor. 48.The mine defined in claim 40, comprising a plurality of pits and atleast one main conveyor outside the pits for transporting mined and/orcollected ore from the pits to a processing plant or a load-out station.